Brief Review of Exosome

Most cells release extracellular microvesicles naturally. These vesicles can be broadly categorized into three subpopulations based on their biological origins and sizes, (1) Apoptotic bodies (800~5,000nm) from the ongoing apoptotic cells; (2) Microvesicles (50~1,000nm), shed from the cellular membrane; and (3) Exosomes (30~150nm), originated from the multivesicular body (Fig.1.). One of the most attractive vesicle types is exosome, which harbors unique subsets of proteins and RNAs. Tetraspanins CD9, CD63, and CD81 were usually found on the surface of the exosome membrane and recognized as the so-called common exosome markers. In addition to these common protein markers, exosomes also contain the tissue-specific proteins and RNAs. The content and amount of exosome proteins and RNAs reflect cellular physiological status and origin. It is becoming clear that exosomes mediate both local and distant signal transduction among cells and tissues in both autocrine and paracrine fashion, through the transfer of exosome proteins and RNAs. Exosomes have been isolated from biofluids including serum or plasma, breast milk, ascites, amniotic fluid, semen, saliva, nasal secretions, cerebrospinal fluid (CSF), bronchoalveolar lavage (BAL), bile, and urine. Therefore, exosomes may represent a precious source for both disease diagnosis and natural vesicles for delivery of therapeutic proteins and/or RNAs.

Facts about Exosome:

Exosomes, the natural nano-scale vesicles, contains RNAs, proteins and lipids.
Exosomes are heterogeneous populations in biofluids.
Exosomes are found in all biofluids, including serum or plasma, breast milk, ascites, amniotic fluid, saliva, nasal secretions, cerebrospinal fluid (CSF), bronchoalveolar lavage (BAL), bile, semen and urine.
Exosomes mediate both local and distant signal transduction among cells and tissues.
The content and amount of exosome proteins and RNAs reflect cellular physiological status and origin.